Graduation Term

Summer 2026

Degree Name

Master of Science (MS)

Department

Department of Geography, Geology, and the Environment

Committee Chair

James Day

Committee Member

Jennifer Gifford

Committee Member

Wondwosen Seyoum

Abstract

This study produced a 1:24000-scale geologic map of the Caribou Creek 7.5-minute quadrangle in the Bighorn Mountains, Wyoming, by integrating field observation and U-Pb zircon age data. The results of this study will contribute to the USGS EDMAP program by subdividing the southern gneiss terrain. The quadrangle occurs almost entirely in the Bighorn National Forest and is in the drainage of Clear and Crazy Woman creeks. Elevations range from 6,800-9,400 ft. The quadrangle is dominated by Archean crystalline rocks of the Wyoming Province Beartooth-Bighorn Magmatic terrane, mainly granodiorite and tonalite gneiss with lesser migmatite. Several orientations and ages of mafic dikes crosscut the host quartzofeldspathic rocks. The dominant structural grain trends NE-SW. An additional 18 isotopic ages are provided by this study spanning over ~145 Ma ranging 2848.9 ± 6.9 Ma to 2994.2 ± 8.4 Ma, which are consistent with other ages available for the Bighorn Mountains southern gneiss terrane. Paleozoic strata, which occur only in the SE part of the Quadrangle, dip moderately to the east and are more than 300 m in thickness and include the Flathead, Gallatin and Gros Venture, and the Bighorn Dolomite. The Paleogene White River Group gravels cap the low-lying areas, and the Quaternary Bull Lake diamicton can be found in the NE area of the map.

Access Type

Thesis-Open Access

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Geology Commons

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